The DACs, ADCs and mixer are integrated with analog I/ Os, which include four analog line-level stereo inputs, two analog line-level mono inputs, two stereo outputs, and one mono output channel. The STAC9766/9767 includes digital input/output capability for support of modern PC systems with an output that supports the SPDIF format. The STAC9766/9767 is a standard 2-channel stereo CODEC. With IDT's headphone drive capability, headphones can be driven with without an external amplifier. The STAC9766/9767 may be used as a secondary CODEC, with the STAC9700/21/56/08/84/50/52 as the primary, in a multiple CODEC configuration conforming to the AC'97 Rev. 2.3 specification. This configuration can provide the true six-channel, AC-3 playback required for DVD applications.